ヘルプを Wiki から分離 (#424) (#430)

画面上でのテストは完了．
移行にす早さが求められるので，準備ができたらマージする．

Reviewed-on: #430
Co-authored-by: miteruzo <miteruzo@naver.com>

backend/spec/requests/materials_spec.rb

@@ -178,6 +178,7 @@ RSpec.describe 'Materials API', type: :request do
   end
 
   describe 'GET /materials/:id' do
+    include WikiRecords
     let!(:tag) do
       create(:tag, primary_name: 'material_show', category: :material)
     end
@@ -205,6 +206,56 @@ RSpec.describe 'Materials API', type: :request do
       get '/materials/999999999'
       expect(response).to have_http_status(:not_found)
     end
+
+    def get_material_without_legacy_reads
+      queries = []
+      subscriber = lambda do |*args|
+        sql = args.last.fetch(:sql)
+        if sql.match?(/\bSELECT\b/i) && sql.match?(/\bwiki_(pages|revisions|versions)\b/i)
+          queries << sql
+        end
+      end
+      ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') do
+        get "/materials/#{ material.id }"
+      end
+      expect(response).to have_http_status(:ok)
+      expect(queries).to be_empty
+    end
+
+    it 'reads the description even when the legacy revision has different content' do
+      page = seed_wiki_page(tag_name: tag.tag_name('ja'), body: 'legacy body',
+                            created_by_user: member_user)
+      TagDescription.find_by!(tag_id: tag.id, language_code: 'ja')
+          .update!(body: 'description body')
+      get_material_without_legacy_reads
+      expect(json.fetch('wiki_page_body')).to eq('description body')
+      expect(page.current_revision.body).to eq('legacy body')
+    end
+
+    it 'uses tag_id rather than description ID without a Wiki page or TagName' do
+      description = TagDescription.create!(id: tag.id + 1000, tag:, language_code: 'ja',
+                                           body: 'independent body', version_no: 1)
+      tag.tag_names.update_all(tag_id: nil)
+      get_material_without_legacy_reads
+      expect(description.id).not_to eq(tag.id)
+      expect(json.fetch('wiki_page_body')).to eq('independent body')
+      expect(json.fetch('tag').fetch('has_wiki')).to be(true)
+    end
+
+    it 'returns nil when only legacy Wiki content exists' do
+      seed_wiki_page(tag_name: tag.tag_name('ja'), body: 'legacy only',
+                     created_by_user: member_user)
+      TagDescription.where(tag_id: tag.id).delete_all
+      get_material_without_legacy_reads
+      expect(json.fetch('wiki_page_body')).to be_nil
+      expect(json.fetch('tag').fetch('has_wiki')).to be(false)
+    end
+
+    it 'returns nil for an untagged material' do
+      material.update!(tag: nil)
+      get_material_without_legacy_reads
+      expect(json.fetch('wiki_page_body')).to be_nil
+    end
   end
 
   describe 'POST /materials' do

backend/spec/requests/tag_description_wiki_spec.rb

@@ -1,16 +1,17 @@
 require 'rails_helper'
 
 RSpec.describe 'Tag description Wiki compatibility', type: :request do
+  include WikiRecords
   let!(:user) { create_member_user! }
   let!(:tag_name) { create(:tag_name, name: 'description_contract') }
   let!(:page) do
-    Wiki::Commit.create_content!(
+    seed_wiki_page(
         tag_name:, body: 'old-revision', created_by_user: user)
   end
   let!(:revisions) do
     first = page.current_revision
-    second = Wiki::Commit.content!(page:, body: 'old-second', created_user: user)
-    third = Wiki::Commit.content!(page:, body: 'old-third', created_user: user)
+    second = Wiki::Commit.legacy_content!(page:, body: 'old-second', created_user: user)
+    third = Wiki::Commit.legacy_content!(page:, body: 'old-third', created_user: user)
     [first, second, third]
   end
   let!(:tag) { create(:tag, primary_tag_name: tag_name) }
@@ -242,8 +243,8 @@ RSpec.describe 'Tag description Wiki compatibility', type: :request do
   end
 
   describe 'mixed changes' do
-    it 'includes unmigrated history and ignores migrated legacy-only revisions' do
-      legacy_page = Wiki::Commit.create_content!(
+    it 'excludes unmigrated history and migrated legacy-only revisions' do
+      legacy_page = seed_wiki_page(
           tag_name: create(:tag_name, name: 'Help_mixed'),
           body: 'help', created_by_user: user)
       legacy_revision = legacy_page.current_revision
@@ -256,7 +257,7 @@ RSpec.describe 'Tag description Wiki compatibility', type: :request do
       migrated = json.select { |row| row.fetch('wiki_page').fetch('id') == description.id }
       expect(migrated.map { |row| row.fetch('revision_id') }).to eq(versions.reverse.map(&:id))
       expect(json.map { |row| row.fetch('revision_id') }).not_to include(extra.id)
-      expect(json).to include(include(
+      expect(json).not_to include(include(
           'revision_id' => legacy_revision.id,
           'wiki_page' => include('id' => legacy_page.id, 'title' => 'Help_mixed')))
     end

backend/spec/requests/tag_description_wiki_write_spec.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe 'Tag description Wiki dual writes', type: :request do
+  include WikiRecords
   let!(:user) { create_member_user! }
   let!(:tag_name) { create(:tag_name, name: 'description_write') }
   let(:tag) { create(:tag, primary_tag_name: tag_name) }
@@ -31,7 +32,7 @@ RSpec.describe 'Tag description Wiki dual writes', type: :request do
            headers: headers
     end
 
-    it 'creates both current records and histories with a shared revision ID' do
+    it 'creates a description with matching Wiki content and histories' do
       expect { create_description }
           .to change(WikiPage, :count).by(1)
           .and change(WikiRevision, :count).by(1)
@@ -39,17 +40,28 @@ RSpec.describe 'Tag description Wiki dual writes', type: :request do
           .and change(TagDescription, :count).by(1)
           .and change(TagDescriptionVersion, :count).by(1)
       expect(response).to have_http_status(:created)
-
-      page = WikiPage.find(json.fetch('id'))
       description = TagDescription.find_by!(tag_id: tag.id, language_code: 'ja')
-      version = TagDescriptionVersion.find_by!(tag_id: tag.id, language_code: 'ja')
-      expect(description).to have_attributes(id: page.id, body: 'initial', version_no: 1)
-      expect(version).to have_attributes(
-          id: page.current_revision.id, body: 'initial', version_no: 1,
-          event_type: 'create', created_by_user_id: user.id)
+      expect(description).to have_attributes(body: 'initial', version_no: 1)
+      page = WikiPage.find_by!(tag_name:)
       expect(page.body).to eq(description.body)
-      expect(page.current_revision.body).to eq(version.body)
-      expect(page.wiki_versions.last.body).to eq(version.body)
+      expect(page.current_revision.body).to eq(description.body)
+      expect(page.wiki_versions.sole.body).to eq(description.body)
+      expect(json.fetch('id')).to eq(description.id)
+      expect(TagDescriptionVersion.find_by!(tag_id: tag.id, language_code: 'ja'))
+          .to have_attributes(body: 'initial', version_no: 1, created_by_user_id: user.id)
+    end
+
+    it 'reuses an existing compatibility page and synchronises its histories' do
+      page = Wiki::Commit.create_legacy_content!(
+          tag_name:, body: 'legacy', created_by_user: user)
+      expect { create_description }
+          .to change(WikiPage, :count).by(0)
+          .and change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
+      expect(response).to have_http_status(:created)
+      description = TagDescription.find_by!(tag_id: tag.id)
+      expect(page.reload.body).to eq(description.body)
+      expect(TagDescriptionVersion.find(page.current_revision.id).body).to eq(page.body)
     end
 
     ['missing_description', 'orphan_description'].each do |title|
@@ -65,48 +77,19 @@ RSpec.describe 'Tag description Wiki dual writes', type: :request do
       end
     end
 
-    it 'creates a namespaced legacy Wiki resource without a Tag' do
-      expect do
-        post '/wiki', params: { title: 'Help:description_write', body: 'legacy' },
-             headers: headers
-      end.to change(WikiPage, :count).by(1)
-          .and change(WikiRevision, :count).by(1)
-          .and change(WikiVersion, :count).by(1)
-          .and change(TagDescription, :count).by(0)
-          .and change(TagDescriptionVersion, :count).by(0)
-
-      expect(response).to have_http_status(:created)
-      page = WikiPage.find(json.fetch('id'))
-      expect(page.tag_name.tag).to be_nil
-      expect(page.body).to eq('legacy')
-      expect(page.current_revision.body).to eq('legacy')
-    end
-
-    it 'creates only legacy Wiki for a namespaced title with an existing Tag' do
-      namespaced_name = create(:tag_name, name: 'help:foo')
-      namespaced_tag = create(:tag, primary_tag_name: namespaced_name)
-
-      expect do
-        post '/wiki', params: { title: namespaced_name.name, body: 'legacy' },
-             headers: headers
-      end.to change(WikiPage, :count).by(1)
-          .and change(WikiRevision, :count).by(1)
-          .and change(WikiVersion, :count).by(1)
-          .and change(TagName, :count).by(0)
-          .and change(TagDescription, :count).by(0)
-          .and change(TagDescriptionVersion, :count).by(0)
-
-      expect(response).to have_http_status(:created)
-      page = WikiPage.find(json.fetch('id'))
-      expect(page).to have_attributes(tag_name_id: namespaced_name.id, body: 'legacy')
-      expect(page.tag_name.tag).to eq(namespaced_tag)
-      expect(page.current_revision.body).to eq('legacy')
-      expect(page.wiki_versions.last.body).to eq('legacy')
+    [false, true].each do |linked|
+      it "rejects namespaced creation with Tag present: #{ linked }" do
+        name = create(:tag_name, name: 'Help:frozen')
+        create(:tag, primary_tag_name: name) if linked
+        before_state = stored_state
+        post '/wiki', params: { title: name.name, body: 'legacy' }, headers: headers
+        expect(response.status).to be_between(400, 499)
+        expect(stored_state).to eq(before_state)
+      end
     end
 
     [WikiPage, WikiRevision, WikiVersion, TagDescription, TagDescriptionVersion].each do |model|
-      it "rolls back both systems when #{ model.name } persistence fails" do
-        tag_name
+      it "rolls back new description creation when #{ model.name } persistence fails" do
         before_state = stored_state
         aggregate_failures do
           fail_save(model) { create_description }
@@ -116,10 +99,32 @@ RSpec.describe 'Tag description Wiki dual writes', type: :request do
     end
   end
 
+  it 'creates missing compatibility data without writing an ID-colliding Help page' do
+    description = TagDescription.create!(
+        id: 500, tag:, language_code: 'ja', body: 'before', version_no: 1)
+    help = WikiPage.create!(id: description.id,
+                            tag_name: create(:tag_name, name: 'Help:unrelated'),
+                            body: 'unrelated', created_user: user, updated_user: user)
+    Wiki::Commit.legacy_content!(page: help, body: help.body, created_user: user)
+    before_help = help.attributes
+    expect do
+      put "/wiki/#{ description.id }", params: { title: tag_name.name, body: 'after' },
+          headers: headers
+    end.to change(WikiPage, :count).by(1)
+        .and change(WikiRevision, :count).by(1)
+        .and change(WikiVersion, :count).by(1)
+    expect(response).to have_http_status(:ok)
+    expect(description.reload).to have_attributes(id: 500, body: 'after')
+    expect(help.reload.attributes).to eq(before_help)
+    compatibility = WikiPage.find_by!(tag_name:)
+    expect(compatibility.body).to eq(description.body)
+    expect(compatibility.current_revision.body).to eq(description.body)
+  end
+
   describe 'PUT /wiki/:id' do
     let!(:page) do
       tag
-      Wiki::Commit.create_content!(
+      seed_wiki_page(
           tag_name:, body: 'before', created_by_user: user)
     end
     let!(:first_revision) { page.current_revision }
@@ -138,7 +143,8 @@ RSpec.describe 'Tag description Wiki dual writes', type: :request do
       expect(page.reload.version_no).to eq(1)
       expect(description.version_no).to eq(1)
       expect { update_description }
-          .to change(WikiRevision, :count).by(1)
+          .to change(WikiPage, :count).by(0)
+          .and change(WikiRevision, :count).by(1)
           .and change(WikiVersion, :count).by(1)
           .and change(TagDescriptionVersion, :count).by(1)
       expect(response).to have_http_status(:ok)
@@ -157,7 +163,8 @@ RSpec.describe 'Tag description Wiki dual writes', type: :request do
       tag_name.update_columns(tag_id: nil)
 
       expect { update_description }
-          .to change(WikiRevision, :count).by(1)
+          .to change(WikiPage, :count).by(0)
+          .and change(WikiRevision, :count).by(1)
           .and change(WikiVersion, :count).by(1)
           .and change(TagDescriptionVersion, :count).by(1)
 
@@ -177,10 +184,10 @@ RSpec.describe 'Tag description Wiki dual writes', type: :request do
       page_state = page.attributes
       description_state = description.attributes
 
-      update_description(body: 'before', title: 'Help:description_renamed')
+      update_description(body: 'before', title: 'description_renamed')
 
       expect(response).to have_http_status(:ok)
-      expect(tag_name.reload.name).to eq('Help:description_renamed')
+      expect(tag_name.reload.name).to eq('description_renamed')
       expect(WikiRevision.count).to eq(revision_count)
       expect(WikiVersion.count).to eq(wiki_version_count)
       expect(TagDescriptionVersion.count).to eq(description_version_count)

backend/spec/requests/tag_descriptions_spec.rb

@@ -206,7 +206,13 @@ RSpec.describe 'Tag description native API', type: :request do
     context 'without an existing description' do
       before { tag }
 
-      it 'creates both current resources and histories with matching compatibility IDs' do
+      it 'creates a description with synchronised Wiki content and histories' do
+        unrelated = Wiki::Commit.create_legacy_content!(
+            tag_name: create(:tag_name, name: 'Help:unrelated_native_description'),
+            body: 'unrelated body', created_by_user: author)
+        unrelated_state = [unrelated.attributes,
+                           unrelated.wiki_revisions.map(&:attributes),
+                           unrelated.wiki_versions.map(&:attributes)]
         expect { native_write(body: 'created natively') }
             .to change(TagDescription, :count).by(1)
             .and change(TagDescriptionVersion, :count).by(1)
@@ -215,7 +221,7 @@ RSpec.describe 'Tag description native API', type: :request do
             .and change(WikiVersion, :count).by(1)
         expect(response).to have_http_status(:created)
         description = TagDescription.find_by!(tag_id: tag.id, language_code: 'ja')
-        page = WikiPage.find(description.id)
+        page = WikiPage.find_by!(tag_name: tag.tag_name('ja'))
         revision = page.current_revision
         version = TagDescriptionVersion.find(revision.id)
         expect(description).to have_attributes(
@@ -227,6 +233,9 @@ RSpec.describe 'Tag description native API', type: :request do
         expect(page).to have_attributes(tag_name_id: tag_name.id, body: description.body)
         expect(revision.body).to eq(version.body)
         expect(page.wiki_versions.last.body).to eq(version.body)
+        unrelated.reload
+        expect([unrelated.attributes, unrelated.wiki_revisions.map(&:attributes),
+                unrelated.wiki_versions.map(&:attributes)]).to eq(unrelated_state)
         expect_current(description)
 
         get "/wiki/#{ description.id }"

backend/spec/requests/tag_group_wiki_spec.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe 'Tag group Wiki facade reads', type: :request do
+  include WikiRecords
   include TagGroupRecords
 
   let!(:user) { create_member_user! }
@@ -69,34 +70,36 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
     end
   end
 
-  it 'combines Tag Groups, Help and Tag Descriptions in the unfiltered list' do
-    help = Wiki::Commit.create_legacy_content!(
+  it 'combines Tag Groups and Tag Descriptions without Help in the unfiltered list' do
+    help = seed_wiki_page(
         tag_name: create(:tag_name, name: 'Help:混在'), body: 'help', created_by_user: user)
     TagDescriptionOperation.create!(tag: new_tag, body: 'tag description', created_by_user: user)
     get '/wiki'
     expect(response).to have_http_status(:ok)
     expect(json.map { _1.fetch('title') }).to include(
-        'タググループ:読取り契約', help.title, '新タグ')
+        'タググループ:読取り契約', '新タグ')
+    expect(json.map { _1.fetch('title') }).not_to include(help.title)
   end
 
-  it 'keeps Help readable when its ID collides with a new group' do
-    help = Wiki::Commit.create_legacy_content!(
+  it 'excludes Help when its ID collides with a new group' do
+    help = seed_wiki_page(
         tag_name: create(:tag_name, name: 'Help:ID重複'), body: 'help body',
         created_by_user: user)
     seed_group(name: '別 ID重複', id: help.id, description: 'group body')
 
     get '/wiki'
     expect(response).to have_http_status(:ok)
-    expect(json.map { _1.fetch('title') }).to include(help.title, 'タググループ:別 ID重複')
+    expect(json.map { _1.fetch('title') }).to include('タググループ:別 ID重複')
+    expect(json.map { _1.fetch('title') }).not_to include(help.title)
 
     get "/wiki/title/#{ CGI.escapeURIComponent(help.title) }"
-    expect(response).to have_http_status(:ok)
-    expect(json.fetch('body')).to eq('help body')
+    expect(response).to have_http_status(:not_found)
 
     get '/wiki/changes'
     expect(response).to have_http_status(:ok)
     expect(json.map { _1.dig('wiki_page', 'title') }).to include(
-        help.title, 'タググループ:別 ID重複')
+        'タググループ:別 ID重複')
+    expect(json.map { _1.dig('wiki_page', 'title') }).not_to include(help.title)
   end
 
   it 'finds groups by a partial prefix of their displayed title' do
@@ -122,7 +125,7 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
   end
 
   it 'orders mixed resource history by timestamp rather than independent IDs' do
-    help = Wiki::Commit.create_legacy_content!(
+    help = seed_wiki_page(
         tag_name: create(:tag_name, name: 'Help:時系列'), body: 'help',
         created_by_user: user)
     TagDescriptionOperation.create!(tag: new_tag, body: 'description', created_by_user: user)
@@ -136,8 +139,8 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
     timestamps = json.map { Time.iso8601(_1.fetch('timestamp')) }
     expect(timestamps).to eq(timestamps.sort.reverse)
     titles = json.map { _1.dig('wiki_page', 'title') }
-    expect(titles.index('新タグ')).to be < titles.index(help.title)
-    expect(titles.index(help.title)).to be < titles.index('タググループ:読取り契約')
+    expect(titles).not_to include(help.title)
+    expect(titles.index('新タグ')).to be < titles.index('タググループ:読取り契約')
   end
 
   it 'renders nullable group editors without raising' do
@@ -166,16 +169,16 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
         'wiki_page' => include('id' => page.id, 'title' => 'タググループ:読取り契約'))
   end
 
-  it 'includes Help and group history but excludes legacy-only migrated revisions' do
+  it 'includes group history but excludes all legacy-only revisions' do
     extra = Wiki::Commit.legacy_content!(page:, body: 'legacy only', created_user: user)
-    help = Wiki::Commit.create_legacy_content!(
+    help = seed_wiki_page(
         tag_name: create(:tag_name, name: 'Help:変更一覧'), body: 'help', created_by_user: user)
     get '/wiki/changes'
     expect(response).to have_http_status(:ok)
     rows = json.select { _1.fetch('wiki_page').fetch('title') == 'タググループ:読取り契約' }
     expect(rows.map { _1.fetch('revision_id') }).to eq([last_revision.id, first_revision.id])
     expect(rows.map { _1.fetch('revision_id') }).not_to include(extra.id)
-    expect(json).to include(include(
+    expect(json).not_to include(include(
         'revision_id' => help.current_revision.id,
         'wiki_page' => include('title' => help.title)))
   end
@@ -214,7 +217,7 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
 
   context 'when Help, description and group share the same numeric ID' do
     let(:colliding_help) do
-      Wiki::Commit.create_legacy_content!(
+      seed_wiki_page(
           tag_name: create(:tag_name, name: 'Help:三者ID衝突'),
           body: 'help', created_by_user: user)
     end
@@ -239,13 +242,12 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
       colliding_description_version
     end
 
-    it 'lists all three resources without deduplicating their numeric ID' do
+    it 'lists both new resources sharing a numeric ID without legacy Help' do
       get '/wiki'
 
       expect(response).to have_http_status(:ok)
       rows = json.select { _1.fetch('id') == colliding_help.id }
       expect(rows.map { [_1.fetch('id'), _1.fetch('title')] }).to contain_exactly(
-          [colliding_help.id, colliding_help.title],
           [colliding_description.id, '新タグ'],
           [colliding_group_id, 'タググループ:三者ID衝突'])
     end
@@ -259,7 +261,6 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
         [row.fetch('revision_id'), row.fetch('wiki_page').fetch('title')]
       end
       expect(histories).to contain_exactly(
-          [colliding_help.current_revision.id, colliding_help.title],
           [colliding_description_version.id, '新タグ'],
           [group_version(colliding_group_id, 1).fetch('id'), 'タググループ:三者ID衝突'])
     end
@@ -285,8 +286,8 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
     end
   end
 
-  it 'resolves colliding group, Help and description IDs by title' do
-    help = Wiki::Commit.create_legacy_content!(
+  it 'resolves new resources by title while excluding colliding legacy Help' do
+    help = seed_wiki_page(
         tag_name: create(:tag_name, name: 'Help:ID衝突'), body: 'help', created_by_user: user)
     seed_group(name: 'ID衝突', id: help.id, description: 'group')
     TagDescription.create!(
@@ -294,11 +295,15 @@ RSpec.describe 'Tag group Wiki facade reads', type: :request do
     TagDescriptionVersion.create!(
         tag_id: new_tag.id, language_code: 'ja', version_no: 1,
         event_type: 'create', body: 'description', created_at: Time.current)
-    { 'タググループ:ID衝突' => 'group', 'Help:ID衝突' => 'help', '新タグ' => 'description' }
+    { 'タググループ:ID衝突' => 'group', '新タグ' => 'description' }
         .each do |title, body|
       get "/wiki/title/#{ CGI.escapeURIComponent(title) }"
       expect(response).to have_http_status(:ok)
       expect(json.fetch('body').strip).to eq(body)
     end
+    without_group_legacy_reads do
+      get "/wiki/title/#{ CGI.escapeURIComponent(help.title) }"
+    end
+    expect(response).to have_http_status(:not_found)
   end
 end

backend/spec/requests/tag_group_wiki_write_spec.rb

@@ -33,8 +33,11 @@ RSpec.describe 'Tag group Wiki facade writes', type: :request do
     end
   end
 
-  it 'creates the group, first snapshot and compatibility Wiki history' do
-    create_group
+  it 'creates the group, snapshot and matching compatibility histories' do
+    expect { create_group }
+        .to change(WikiPage, :count).by(1)
+        .and change(WikiRevision, :count).by(1)
+        .and change(WikiVersion, :count).by(1)
     expect(response).to have_http_status(:created)
     group = group_rows('tag_groups', name: '新規').sole
     expect(json).to include('id' => group.fetch('id'), 'title' => 'タググループ:新規')
@@ -43,10 +46,9 @@ RSpec.describe 'Tag group Wiki facade writes', type: :request do
     expect(version).to include('event_type' => 'create', 'created_by_user_id' => user.id)
     expect(group).to include('created_by_user_id' => user.id, 'updated_by_user_id' => user.id)
     page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:新規' })
-    expect(page.body.strip).to eq('- 洗澡鹿')
+    expect(page.body).to eq('- 洗澡鹿')
     expect(page.current_revision.body).to eq(page.body)
     expect(page.wiki_versions.sole.body).to eq(page.body)
-    # New IDs are independently allocated; no global identity assertion here.
   end
 
   it 'keeps repeated placements but only one membership and one snapshot member' do
@@ -293,8 +295,9 @@ RSpec.describe 'Tag group Wiki facade writes', type: :request do
         expect(group_state).to eq(before_state)
       end
 
-      (TagGroupRecords::GROUP_TABLES + ['wiki_pages', 'wiki_revisions', 'wiki_versions'])
-          .each do |table|
+      tables = TagGroupRecords::GROUP_TABLES
+      tables += ['wiki_pages', 'wiki_revisions', 'wiki_versions']
+      tables.each do |table|
         it "rolls back all writes after a real #{ table } write fails" do
           expect_atomic_group_write(table) { write_group(operation, headers) }
         end

backend/spec/requests/tag_group_write_integrity_spec.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe 'Tag group write integrity', type: :request do
+  include WikiRecords
   include TagGroupRecords
   include ActiveSupport::Testing::TimeHelpers
 
@@ -24,7 +25,7 @@ RSpec.describe 'Tag group write integrity', type: :request do
   end
 
   def create_help body
-    Wiki::Commit.create_legacy_content!(
+    seed_wiki_page(
         tag_name: create(:tag_name, name: 'Help:既存'), body:, created_by_user: user)
   end
 
@@ -70,17 +71,16 @@ RSpec.describe 'Tag group write integrity', type: :request do
       expect(page.body).to eq('- 伊地知ニジカ')
     end
 
-    it 'updates Help with a colliding group ID without altering the group' do
+    it 'rejects a standalone Help update despite a colliding group ID' do
       page = create_help('Help body')
       id = seed_group(name: '別グループ', id: page.id, members:, placements:)
       group_before = TagGroup.find(id).attributes
       version_before = group_version(id, 1)
 
-      put_wiki(id, title: 'Help:改名', body: 'Help after')
+      expect_no_writes { put_wiki(id, title: 'Help:改名', body: 'Help after') }
 
-      expect(response).to have_http_status(:ok)
-      expect(page.reload.body).to eq('Help after')
-      expect(page.title).to eq('Help:改名')
+      expect(page.reload.body).to eq('Help body')
+      expect(page.title).to eq('Help:既存')
       expect(TagGroup.find(id).attributes).to eq(group_before)
       expect(group_version(id, 1)).to eq(version_before)
     end
@@ -98,7 +98,8 @@ RSpec.describe 'Tag group write integrity', type: :request do
     it 'keeps a description update separate from a colliding group' do
       page = Wiki::Commit.create_content!(
           tag_name: tag.tag_name('ja'), body: 'description before', created_by_user: user)
-      id = seed_group(name: '更新', id: page.id, members:, placements:)
+      description = TagDescription.find_by!(tag_id: tag.id)
+      id = seed_group(name: '更新', id: description.id, members:, placements:)
       group_before = TagGroup.find(id).attributes
 
       put_wiki(id, title: '洗澡鹿', body: 'description after')
@@ -115,18 +116,19 @@ RSpec.describe 'Tag group write integrity', type: :request do
       description = TagDescription.create!(
           id:, tag:, language_code: 'ja', version_no: 1, body: 'description')
 
-      put_wiki(id, title: 'Help:既存', body: 'Help after')
+      expect_no_writes { put_wiki(id, title: 'Help:既存', body: 'Help after') }
 
-      expect(response).to have_http_status(:ok)
-      expect(page.reload.body).to eq('Help after')
+      expect(page.reload.body).to eq('Help before')
       expect(description.reload.body).to eq('description')
       expect(TagGroup.find(id).version_no).to eq(1)
-      expect_no_writes { put_wiki(id, title: '洗澡鹿', body: 'description after') }
+      put_wiki(id, title: '洗澡鹿', body: 'description after')
+      expect(response).to have_http_status(:ok)
+      expect(description.reload.body).to eq('description after')
       put_wiki(id, title: 'タググループ:更新')
       expect(response).to have_http_status(:ok)
       expect(TagGroup.find(id).version_no).to eq(2)
-      expect(page.reload.body).to eq('Help after')
-      expect(description.reload.body).to eq('description')
+      expect(page.reload.body).to eq('Help before')
+      expect(description.reload.body).to eq('description after')
     end
   end
 
@@ -136,14 +138,14 @@ RSpec.describe 'Tag group write integrity', type: :request do
       id = seed_group(name: '更新', id: help.id, members:, placements:)
       help_before = help.attributes
 
-      put "/tag_groups/#{ id }", params: native_payload(name: '改名'), headers:, as: :json
+      expect do
+        put "/tag_groups/#{ id }", params: native_payload(name: '改名'), headers:, as: :json
+      end.to change(WikiPage, :count).by(1)
+          .and change(WikiRevision, :count).by(1)
+          .and change(WikiVersion, :count).by(1)
 
       expect(response).to have_http_status(:ok)
-      page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:改名' })
-      expect(page.id).not_to eq(help.id)
-      expect(page.body).to eq('- 洗澡鹿')
-      expect(page.current_revision.body).to eq(page.body)
-      expect(page.wiki_versions.sole.body).to eq(page.body)
+      expect(TagGroup.find(id).name).to eq('改名')
       expect(help.reload.attributes).to eq(help_before)
     end
 

backend/spec/requests/tag_groups_spec.rb

@@ -391,6 +391,17 @@ RSpec.describe 'Tag group native API', type: :request do
         end
       end
 
+      it 'creates native state and its compatibility histories' do
+        expect { native_write(:create) }
+            .to change(WikiPage, :count).by(1)
+            .and change(WikiRevision, :count).by(1)
+            .and change(WikiVersion, :count).by(1)
+        expect(response).to have_http_status(:created)
+        expect_group_snapshot(
+            json.fetch('id'), number: 1, members: snapshot_members,
+            placements:, description: '全体の説明')
+      end
+
       [:create, :update].each do |operation|
         it "synchronises Wiki current state and histories on native #{ operation }" do
           native_write(operation)
@@ -418,19 +429,18 @@ RSpec.describe 'Tag group native API', type: :request do
         end
       end
 
-      it 'uses AUTO_INCREMENT for a new group instead of supplying a compatibility ID' do
-        inserts = []
-        subscriber = lambda do |*args|
-          sql = args.last.fetch(:sql)
-          inserts << sql if sql.match?(/\A\s*INSERT INTO `?tag_groups`?\s/i)
-        end
-        ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') do
-          native_write(:create)
-        end
+      it 'assigns the next group ID from the existing maximum' do
+        child_id
+        expected_id = [TagGroup.maximum(:id).to_i, TagDescription.maximum(:id).to_i].max + 1
+        native_write(:create)
         expect(response).to have_http_status(:created)
-        expect(inserts.size).to eq(1)
-        columns = inserts.sole[/\((.*?)\)/, 1].split(',').map { _1.strip.delete('`') }
-        expect(columns).not_to include('id')
+        expect(json.fetch('id')).to eq(expected_id)
+      end
+
+      TagGroupRecords::GROUP_TABLES.each do |table|
+        it "rolls back native creation after #{ table } writes" do
+          expect_atomic_group_write(table) { native_write(:create) }
+        end
       end
 
       it 'updates a native group through Wiki and then reads structured current data' do

backend/spec/requests/tag_resource_ids_spec.rb

@@ -0,0 +1,101 @@
+require 'rails_helper'
+
+RSpec.describe 'Tag resource ID allocation', type: :request do
+  include TagGroupRecords
+  include WikiRecords
+
+  let!(:user) { create_member_user! }
+  let(:headers) { { 'X-Transfer-Code' => user.inheritance_code } }
+
+  def seed_description id
+    tag = create(:tag, primary_name: "description_id_#{ id }")
+    TagDescription.create!(id:, tag:, language_code: 'ja', body: 'existing', version_no: 1)
+  end
+
+  def create_resource resource
+    if resource == :description
+      tag = create(:tag, primary_name: 'new_description')
+      post '/wiki', params: { title: tag.name('ja'), body: 'new description' }, headers: headers
+    else
+      post '/tag_groups', params: {
+          name: 'new_group', description: 'new group', members: [], placements: [] },
+          headers:, as: :json
+    end
+    expect(response).to have_http_status(:created)
+  end
+
+  [:description, :group].each do |resource|
+    it "keeps #{ resource } independent of the Tag and ExternalTag ID space" do
+      create(:tag, id: 100)
+      create(:external_tag, id: 200)
+      seed_description(1)
+      seed_group(name: 'shared_space', id: 2)
+
+      create_resource(resource)
+
+      expect(json.fetch('id')).to eq(3)
+    end
+
+    it "uses the other resource's larger maximum when allocating #{ resource }" do
+      seed_description(resource == :description ? 1 : 20)
+      seed_group(name: 'other_space', id: resource == :group ? 1 : 20)
+      create_resource(resource)
+      expect(json.fetch('id')).to eq(21)
+    end
+
+    it "starts #{ resource } at 1 even after previous allocated rows were removed" do
+      expect(TagDescription.count).to eq(0)
+      expect(TagGroup.count).to eq(0)
+      if resource == :description
+        seed_description(100).destroy!
+      else
+        id = seed_group(name: 'removed', id: 100)
+        TagGroup.find(id).destroy!
+      end
+      create_resource(resource)
+      expect(json.fetch('id')).to eq(1)
+    end
+
+    it "allocates #{ resource } above both maxima, preserving legacy overlaps and gaps" do
+      [1, 2, 5].each { seed_description(_1) }
+      [1, 3, 8].each { seed_group(name: "group_#{ _1 }", id: _1) }
+      descriptions = TagDescription.order(:id).map(&:attributes)
+      groups = TagGroup.order(:id).map(&:attributes)
+
+      create_resource(resource)
+
+      expect(json.fetch('id')).to eq(9)
+      expect(TagDescription.where(id: [1, 2, 5]).order(:id).map(&:attributes)).to eq(descriptions)
+      expect(TagGroup.where(id: [1, 3, 8]).order(:id).map(&:attributes)).to eq(groups)
+      expect(TagDescription.exists?(id: 3)).to be(false)
+      expect(TagGroup.exists?(id: 2)).to be(false)
+    end
+  end
+
+  it 'preserves group ID and unrelated rows on update' do
+    id = seed_group(name: 'existing', id: 5, description: 'before')
+    other_id = seed_group(name: 'other', id: 8, description: 'other')
+    other = TagGroup.find(other_id).attributes
+    put "/tag_groups/#{ id }", params: {
+        name: 'renamed', description: 'after', members: [], placements: [] }, headers:, as: :json
+    expect(response).to have_http_status(:ok)
+    expect(json.fetch('id')).to eq(id)
+    expect(TagGroup.find(id).description).to eq('after')
+    expect(TagGroup.find(other_id).attributes).to eq(other)
+    expect(TagGroup.count).to eq(2)
+  end
+
+  it 'preserves description identity on a compatibility update' do
+    tag = create(:tag, primary_name: 'existing_description')
+    page = seed_wiki_page(tag_name: tag.tag_name('ja'), body: 'before', created_by_user: user)
+    description = TagDescription.find_by!(tag_id: tag.id, language_code: 'ja')
+    id = description.id
+    put "/wiki/#{ id }", params: {
+        title: tag.name('ja'), body: 'after', base_revision_id: page.current_revision.id },
+        headers: headers
+    expect(response).to have_http_status(:ok)
+    expect(description.reload.id).to eq(id)
+    expect(description.body).to eq('after')
+    expect(TagDescription.count).to eq(1)
+  end
+end

backend/spec/requests/tag_wiki_history_integrity_spec.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe 'Tag and wiki history integrity', type: :request do
+  include WikiRecords
   let(:member_user) { create(:user, role: 'member') }
 
   def stub_current_user user
@@ -13,7 +14,7 @@ RSpec.describe 'Tag and wiki history integrity', type: :request do
   end
 
   def create_wiki_for_tag! tag:, body: 'wiki body', user: member_user
-    Wiki::Commit.create_content!(
+    seed_wiki_page(
         tag_name: primary_tag_name_for(tag, 'ja'),
         body:,
         created_by_user: user,

backend/spec/requests/tags_spec.rb

@@ -38,6 +38,22 @@ RSpec.describe 'Tags API', type: :request do
   end
 
   describe 'GET /tags' do
+    it 'serialises descriptions and parents without loading legacy Wiki pages' do
+      TagDescription.create!(tag:, language_code: 'ja', body: '', version_no: 1)
+      TagDescription.create!(tag: tag2, language_code: 'ja', body: '', version_no: 1)
+      TagImplication.create!(tag:, parent_tag: tag2)
+      queries = []
+      subscriber = ->(*args) { queries << args.last.fetch(:sql) }
+      ActiveSupport::Notifications.subscribed(subscriber, 'sql.active_record') do
+        get '/tags', params: { name: 'spec_tag' }
+      end
+      expect(response).to have_http_status(:ok)
+      row = response_tags.sole
+      expect(row.fetch('has_wiki')).to be(true)
+      expect(row.fetch('parents').sole.fetch('has_wiki')).to be(true)
+      expect(queries.grep(/\bSELECT\b.*\bwiki_(pages|revisions|versions)\b/im)).to be_empty
+    end
+
     it 'includes legacy external JSON alongside an internal tag with the same id' do
       external = create(:external_tag, id: tag.id, name: 'spec_external', post_count: 3)
 

backend/spec/requests/wiki_conflict_spec.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe 'Wiki conflict handling', type: :request do
+  include WikiRecords
   let!(:user) { create_member_user! }
 
   def auth_headers user
@@ -9,8 +10,8 @@ RSpec.describe 'Wiki conflict handling', type: :request do
 
   it 'returns 409 when base_revision_id is stale' do
     page =
-        Wiki::Commit.create_content!(
-            tag_name: create(:tag_name, name: 'wiki_conflict_request'),
+        seed_wiki_page(
+            tag_name: create(:tag, primary_name: 'wiki_conflict_request').tag_name('ja'),
             body: 'first',
             created_by_user: user,
             message: 'init')
@@ -25,12 +26,10 @@ RSpec.describe 'Wiki conflict handling', type: :request do
         base_revision_id: stale_id)
 
     put "/wiki/#{ page.id }",
-        params: {
-          title: 'wiki_conflict_request',
-          body: 'third',
-          message: 'stale',
-          base_revision_id: stale_id,
-        },
+        params: { title: 'wiki_conflict_request',
+                  body: 'third',
+                  message: 'stale',
+                  base_revision_id: stale_id },
         headers: auth_headers(user)
 
     expect(response).to have_http_status(:conflict)

backend/spec/requests/wiki_creation_freeze_spec.rb

@@ -0,0 +1,63 @@
+require 'rails_helper'
+
+RSpec.describe 'Wiki creation freeze', type: :request do
+  include TagGroupRecords
+  include WikiRecords
+
+  let!(:user) { create_member_user! }
+  let(:headers) { { 'X-Transfer-Code' => user.inheritance_code } }
+
+  it 'creates missing compatibility history when updating an independent group' do
+    id = seed_group(name: 'independent', description: 'before')
+    expect do
+      put "/tag_groups/#{ id }", params: {
+          name: 'independent', description: 'after', members: [], placements: [] },
+          headers:, as: :json
+    end.to change(WikiPage, :count).by(1)
+        .and change(WikiRevision, :count).by(1)
+        .and change(WikiVersion, :count).by(1)
+    expect(response).to have_http_status(:ok)
+    expect(TagGroup.find(id).description).to eq('after')
+    page = WikiPage.joins(:tag_name).find_by!(tag_names: { name: 'タググループ:independent' })
+    expect(page.body).to include('after')
+    expect(page.current_revision.body).to eq(page.body)
+    expect(page.wiki_versions.sole.body).to eq(page.body)
+  end
+
+  context 'existing description write protection' do
+    let!(:tag) { create(:tag, primary_name: 'protected_description') }
+    let!(:page) do
+      seed_wiki_page(tag_name: tag.tag_name('ja'), body: 'before', created_by_user: user)
+    end
+
+    [nil, :guest, :banned].each do |role|
+      it "rejects #{ role || 'anonymous' } without changing either history" do
+        actor = role && create(:user, role == :banned ? :member : role)
+        actor.update!(banned_at: Time.current) if role == :banned
+        request_headers = actor ? { 'X-Transfer-Code' => actor.inheritance_code } : { }
+        before_state = group_state
+        put "/wiki/#{ page.id }", params: { title: tag.name('ja'), body: 'after' },
+            headers: request_headers
+        expect(response).to have_http_status(role ? :forbidden : :unauthorized)
+        expect(group_state).to eq(before_state)
+      end
+    end
+
+    it 'rejects banned IPs without writes' do
+      IpAddress.create!(ip_address: IPAddr.new('127.0.0.1').hton, banned_at: Time.current)
+      before_state = group_state
+      put "/wiki/#{ page.id }", params: { title: tag.name('ja'), body: 'after' }, headers: headers
+      expect(response).to have_http_status(:forbidden)
+      expect(group_state).to eq(before_state)
+    end
+
+    ['', "\r\n\r\n"].each do |body|
+      it "rejects invalid description body #{ body.inspect } atomically" do
+        before_state = group_state
+        put "/wiki/#{ page.id }", params: { title: tag.name('ja'), body: }, headers: headers
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(group_state).to eq(before_state)
+      end
+    end
+  end
+end

backend/spec/requests/wiki_history_integrity_spec.rb

@@ -2,6 +2,7 @@ require 'cgi'
 require 'rails_helper'
 
 RSpec.describe 'Wiki history integrity', type: :request do
+  include WikiRecords
   let!(:user) { create_member_user! }
 
   def auth_headers user
@@ -9,49 +10,22 @@ RSpec.describe 'Wiki history integrity', type: :request do
   end
 
   def create_wiki_page title:, body: 'body', message: 'init', user: self.user
-    Wiki::Commit.create_content!(
-        tag_name: create(:tag_name, name: title),
+    seed_wiki_page(
+        tag_name: create(:tag, primary_name: title).tag_name('ja'),
         body:,
         created_by_user: user,
         message:)
   end
 
   describe 'POST /wiki' do
-    it 'creates wiki_page, wiki_revision, and wiki_version atomically' do
-      expect {
-        post '/wiki',
-             params: {
-               title: 'Help:wiki_history_create_atomic',
-               body: "a\nb\nc",
-               message: 'initial commit',
-             },
+    it 'rejects frozen creation without partial page or history' do
+      expect do
+        post '/wiki', params: { title: 'Help:wiki_history_create_atomic', body: 'initial' },
              headers: auth_headers(user)
-      }
-          .to change(WikiPage, :count).by(1)
-          .and change(WikiRevision, :count).by(1)
-          .and change(WikiVersion, :count).by(1)
-
-      expect(response).to have_http_status(:created)
-
-      page = WikiPage.find(json.fetch('id'))
-      revision = page.current_revision
-      version = page.wiki_versions.order(:version_no).last
-
-      expect(page.title).to eq('Help:wiki_history_create_atomic')
-      expect(page.body).to eq("a\nb\nc")
-
-      expect(revision).to be_content
-      expect(revision.message).to eq('initial commit')
-      expect(revision.lines_count).to eq(3)
-
-      expect(version).to have_attributes(
-        version_no: 1,
-        event_type: 'create',
-        title: 'Help:wiki_history_create_atomic',
-        body: "a\nb\nc",
-        reason: 'initial commit',
-        created_by_user_id: user.id
-      )
+      end.to change(WikiPage, :count).by(0)
+          .and change(WikiRevision, :count).by(0)
+          .and change(WikiVersion, :count).by(0)
+      expect(response.status).to be_between(400, 499)
     end
 
     it 'returns 422 and creates nothing when normalised body is blank' do
@@ -71,21 +45,19 @@ RSpec.describe 'Wiki history integrity', type: :request do
           .where(tag_names: { name: 'Help:wiki_history_blank_body' })).not_to exist
     end
 
-    it 'returns 422 and creates no partial page when title already exists' do
+    it 'rejects frozen creation without modifying an existing page or history' do
       create_wiki_page(title: 'Help:wiki_history_duplicate_title', body: 'first')
 
-      expect {
+      expect do
         post '/wiki',
-             params: {
-               title: 'Help:wiki_history_duplicate_title',
-               body: 'second',
-               message: 'duplicate',
-             },
+             params: { title: 'Help:wiki_history_duplicate_title',
+                       body: 'second', message: 'duplicate' },
              headers: auth_headers(user)
-      }
-          .not_to change(WikiPage, :count)
+      end.to change(WikiPage, :count).by(0)
+          .and change(WikiRevision, :count).by(0)
+          .and change(WikiVersion, :count).by(0)
 
-      expect(response).to have_http_status(:unprocessable_entity)
+      expect(response.status).to be_between(400, 499)
       expect(WikiPage.joins(:tag_name)
           .where(tag_names: { name: 'Help:wiki_history_duplicate_title' }).count).to eq(1)
     end

backend/spec/requests/wiki_index_order_spec.rb

@@ -0,0 +1,42 @@
+require 'rails_helper'
+
+RSpec.describe 'Wiki resource ordering', type: :request do
+  include TagGroupRecords
+  let(:user) { create_member_user! }
+
+  it 'selects the latest twenty across both resources before applying the global limit' do
+    start = Time.utc(2026, 1, 1)
+    descriptions = 24.times.map do |index|
+      tag = create(:tag, primary_name: "rank_#{ index }")
+      TagDescription.create!(tag:, language_code: 'ja', body: 'current', version_no: 1,
+                             updated_at: start + index.hours)
+    end
+    groups = [24, 25].map do |hour|
+      group = TagGroup.find(seed_group(name: "rank_group_#{ hour }"))
+      group.update_columns(updated_at: start + hour.hours)
+      group
+    end
+
+    get '/wiki', params: { title: 'rank' }
+
+    expect(response).to have_http_status(:ok)
+    expected = groups.reverse.map { ['tag_group', _1.id] } +
+        descriptions.last(18).reverse.map { ['tag_description', _1.id] }
+    expect(json.map { [_1.fetch('resource_type'), _1.fetch('id')] }).to eq(expected)
+  end
+
+  it 'breaks timestamp ties by resource kind and ID while retaining legacy overlaps' do
+    time = Time.utc(2026, 1, 1)
+    tag = create(:tag, primary_name: 'tied')
+    TagDescription.create!(id: 51, tag:, language_code: 'ja', body: 'current',
+                           version_no: 1, updated_at: time)
+    group = TagGroup.find(seed_group(name: 'tied', id: 51))
+    group.update_columns(updated_at: time)
+
+    2.times do
+      get '/wiki', params: { title: 'tied' }
+      expect(json.map { [_1.fetch('resource_type'), _1.fetch('id')] })
+          .to eq([['tag_description', 51], ['tag_group', 51]])
+    end
+  end
+end

backend/spec/requests/wiki_spec.rb

@@ -4,6 +4,7 @@ require 'securerandom'
 
 
 RSpec.describe 'Wiki API', type: :request do
+  include WikiRecords
   def auth_headers(user)
     { 'X-Transfer-Code' => user.inheritance_code }
   end
@@ -18,7 +19,7 @@ RSpec.describe 'Wiki API', type: :request do
         deprecated_at: Time.zone.local(2026, 6, 1))
   end
   let!(:page) do
-    Wiki::Commit.create_content!(
+    seed_wiki_page(
         tag_name: tn,
         body: 'init',
         created_by_user: user,
@@ -108,94 +109,14 @@ RSpec.describe 'Wiki API', type: :request do
       end
     end
 
-    context 'when success' do
-      it 'creates wiki_page and first content revision' do
+    ['Help:TestPage', 'ヘルプ:ホーム'].each do |title|
+      it "rejects frozen creation of #{ title } without history writes" do
         expect do
-          post endpoint, params: { title: 'Help:TestPage', body: "a\nb\nc", message: 'init' },
-                         headers: auth_headers(member)
-        end
-            .to change(WikiPage, :count).by(1)
-            .and change(WikiRevision, :count).by(1)
-            .and change(WikiVersion, :count).by(1)
-
-        expect(response).to have_http_status(:created)
-
-        page_id = json.fetch('id')
-        expect(json.fetch('title')).to eq('Help:TestPage')
-
-        created_page = WikiPage.find(page_id)
-        version = created_page.wiki_versions.order(:version_no).last
-
-        expect(version).to have_attributes(
-          version_no: 1,
-          event_type: 'create',
-          title: 'Help:TestPage',
-          body: "a\nb\nc",
-          created_by_user_id: member.id
-        )
-
-        rev = created_page.current_revision
-        expect(rev).to be_present
-        expect(rev).to be_content
-        expect(rev.message).to eq('init')
-
-        expect(created_page.body).to eq("a\nb\nc")
-
-        expect(rev.lines_count).to eq(3)
-        expect(rev.wiki_revision_lines.order(:position).pluck(:position)).to eq([0, 1, 2])
-        expect(rev.wiki_lines.pluck(:body)).to match_array(['a', 'b', 'c'])
-      end
-
-      it 'reuses existing WikiLine rows by sha256' do
-        # 先に同じ行を作っておく
-        WikiLine.create!(sha256: Digest::SHA256.hexdigest('a'), body: 'a', created_at: Time.current, updated_at: Time.current)
-
-        post endpoint,
-             params: { title: 'Help:Reuse', body: "a\na" },
-             headers: auth_headers(member)
-
-        page = WikiPage.find(JSON.parse(response.body).fetch('id'))
-        rev = page.current_revision
-        expect(rev.lines_count).to eq(2)
-
-        # "a" の WikiLine が増殖しない（1行のはず）
-        expect(WikiLine.where(body: 'a').count).to eq(1)
-      end
-
-      it 'deduplicates duplicated new lines before upsert' do
-        duplicated = 'duplicated_line_for_wiki_line_upsert_spec'
-
-        post endpoint,
-             params: { title: 'Help:DuplicateNewLine', body: "#{ duplicated }\n#{ duplicated }" },
-             headers: auth_headers(member)
-
-        expect(response).to have_http_status(:created)
-
-        page = WikiPage.find(json.fetch('id'))
-        rev = page.current_revision
-
-        expect(rev.lines_count).to eq(2)
-        expect(WikiLine.where(body: duplicated).count).to eq(1)
-        expect(rev.wiki_revision_lines.count).to eq(2)
-        expect(rev.wiki_revision_lines.pluck(:wiki_line_id).uniq.size).to eq(1)
-      end
-
-      it 'normalises CRLF and strips trailing newlines' do
-        post endpoint,
-             params: { title: 'Help:NormalisedBody',
-                       body: "a\r\nb\r\n\r\n", message: 'normalise' },
-             headers: auth_headers(member)
-
-        expect(response).to have_http_status(:created)
-
-        page = WikiPage.find(json.fetch('id'))
-        rev = page.current_revision
-        version = page.wiki_versions.order(:version_no).last
-
-        expect(page.body).to eq("a\nb")
-        expect(version.body).to eq("a\nb")
-        expect(rev.lines_count).to eq(2)
-        expect(rev.wiki_lines.order('wiki_revision_lines.position').map(&:body)).to eq(['a', 'b'])
+          post endpoint, params: { title:, body: 'initial' }, headers: auth_headers(member)
+        end.to change(WikiPage, :count).by(0)
+            .and change(WikiRevision, :count).by(0)
+            .and change(WikiVersion, :count).by(0)
+        expect(response.status).to be_between(400, 499)
       end
     end
   end
@@ -208,10 +129,10 @@ RSpec.describe 'Wiki API', type: :request do
       { 'X-Transfer-Code' => user.inheritance_code }
     end
 
-    let!(:test_tag_name) { create(:tag_name, name: 'TestPage') }
+    let!(:test_tag_name) { create(:tag, primary_name: 'TestPage').tag_name('ja') }
 
     let!(:page) do
-      Wiki::Commit.create_content!(
+      seed_wiki_page(
           tag_name: test_tag_name,
           body: "a\nb",
           created_by_user: member,
@@ -249,7 +170,8 @@ RSpec.describe 'Wiki API', type: :request do
 
         expect do
           put "/wiki/#{page.id}",
-              params: { title: 'TestPage', body: "x\ny", message: 'edit', base_revision_id: current_id },
+              params: { title: 'TestPage', body: "x\ny", message: 'edit',
+                        base_revision_id: current_id },
               headers: auth_headers(member)
         end
             .to change(WikiRevision, :count).by(1)
@@ -284,7 +206,7 @@ RSpec.describe 'Wiki API', type: :request do
             created_by_user: member)
 
         linked_page =
-            Wiki::Commit.create_content!(
+            seed_wiki_page(
                 tag_name: linked_tag_name,
                 body: 'before',
                 created_by_user: member,
@@ -358,13 +280,14 @@ RSpec.describe 'Wiki API', type: :request do
 
   describe 'GET /wiki/search' do
     before do
-      Wiki::Commit.create_content!(
-          tag_name: create(:tag_name, name: 'spec_wiki_title_2'),
+      search_tag = create(:tag, primary_name: 'spec_wiki_title_2')
+      seed_wiki_page(
+          tag_name: search_tag.tag_name('ja'),
           body: 'search body 2',
           created_by_user: user,
           message: 'init')
 
-      Wiki::Commit.create_content!(
+      seed_wiki_page(
           tag_name: create(:tag_name, name: 'unrelated_title'),
           body: 'unrelated body',
           created_by_user: user,
@@ -516,7 +439,7 @@ RSpec.describe 'Wiki API', type: :request do
     it 'raises because redirect revisions are deprecated' do
       target_tag_name = create(:tag_name, name: 'redirect_deprecated_target')
       target =
-          Wiki::Commit.create_content!(
+          seed_wiki_page(
               tag_name: target_tag_name,
               body: 'target',
               created_by_user: user,
@@ -539,7 +462,7 @@ RSpec.describe 'Wiki API', type: :request do
     linked_tag = create(:tag, primary_tag_name: linked_tag_name, category: :general)
 
     linked_page =
-        Wiki::Commit.create_content!(
+        seed_wiki_page(
             tag_name: linked_tag_name,
             body: 'before',
             created_by_user: user,

backend/spec/requests/wiki_title_collision_spec.rb

@@ -1,6 +1,7 @@
 require 'rails_helper'
 
 RSpec.describe 'Wiki title collision', type: :request do
+  include WikiRecords
   let!(:user) { create_member_user! }
 
   def auth_headers user
@@ -8,7 +9,7 @@ RSpec.describe 'Wiki title collision', type: :request do
   end
 
   def create_wiki_page title:, body:
-    Wiki::Commit.create_content!(
+    seed_wiki_page(
         tag_name: create(:tag_name, name: title),
         body:,
         created_by_user: user,
@@ -43,20 +44,18 @@ RSpec.describe 'Wiki title collision', type: :request do
     expect(source.wiki_versions.count).to eq(source_version_count)
   end
 
-  it 'returns 422 when creating wiki with existing title' do
+  it 'rejects frozen creation with an existing title without adding history' do
     create_wiki_page(title: 'Help:wiki_collision_create', body: 'already exists')
 
-    expect {
+    expect do
       post '/wiki',
-           params: {
-             title: 'Help:wiki_collision_create',
-             body: 'new body',
-             message: 'duplicate create',
-           },
+           params: { title: 'Help:wiki_collision_create', body: 'new body',
+                     message: 'duplicate create' },
            headers: auth_headers(user)
-    }
-        .not_to change(WikiPage, :count)
+    end.to change(WikiPage, :count).by(0)
+        .and change(WikiRevision, :count).by(0)
+        .and change(WikiVersion, :count).by(0)
 
-    expect(response).to have_http_status(:unprocessable_entity)
+    expect(response.status).to be_between(400, 499)
   end
 end

backend/spec/requests/wiki_unmigrated_contract_spec.rb

@@ -1,115 +1,78 @@
 require 'rails_helper'
 
 RSpec.describe 'Unmigrated Wiki compatibility', type: :request do
+  include WikiRecords
   let!(:user) { create_member_user! }
   let!(:tag_name) { create(:tag_name, name: 'Help_contract') }
   let!(:page) do
-    Wiki::Commit.create_content!(tag_name:, body: 'before', created_by_user: user)
+    seed_wiki_page(tag_name:, body: 'before', created_by_user: user)
   end
   let!(:first_revision) { page.current_revision }
   let!(:last_revision) do
-    Wiki::Commit.content!(page:, body: 'after', created_user: user,
-                          message: 'legacy edit', base_revision_id: first_revision.id)
+    Wiki::Commit.legacy_content!(page:, body: 'after', created_user: user,
+                                 message: 'legacy edit', base_revision_id: first_revision.id)
   end
 
   before { expect(TagDescription.exists?(id: page.id)).to be(false) }
 
-  it 'keeps a Tag-linked legacy page in the legacy domain when its title changes' do
+  it 'rejects standalone updates even after a Tag is linked to the legacy page' do
     create(:tag, primary_tag_name: tag_name)
+    original = page.reload.attributes
 
     expect do
       put "/wiki/#{ page.id }",
           params: { title: 'legacy_tag_renamed', body: 'changed legacy body',
                     message: 'legacy rename', base_revision_id: last_revision.id },
           headers: { 'X-Transfer-Code' => user.inheritance_code }
-    end.to change(WikiRevision, :count).by(1)
-        .and change(WikiVersion, :count).by(1)
+    end.to change(WikiRevision, :count).by(0)
+        .and change(WikiVersion, :count).by(0)
         .and change(TagDescription, :count).by(0)
         .and change(TagDescriptionVersion, :count).by(0)
 
-    expect(response).to have_http_status(:ok)
-    expect(page.reload).to have_attributes(body: 'changed legacy body')
-    expect(page.title).to eq('legacy_tag_renamed')
-    expect(page.current_revision).to have_attributes(message: 'legacy rename')
+    expect(response).to have_http_status(:unprocessable_entity)
+    expect(page.reload.attributes).to eq(original)
+    expect(page.current_revision).to have_attributes(message: 'legacy edit')
   end
 
-  it 'shows legacy current and historical content by ID' do
-    get "/wiki/#{ page.id }"
-    expect(response).to have_http_status(:ok)
-    expect(json).to include('body' => 'after', 'revision_id' => last_revision.id,
-                           'pred' => first_revision.id, 'succ' => nil)
-    get "/wiki/#{ page.id }", params: { version: first_revision.id }
-    expect(response).to have_http_status(:ok)
-    expect(json).to include('body' => 'before', 'revision_id' => first_revision.id,
-                           'pred' => nil, 'succ' => last_revision.id)
+  include TagGroupRecords
+
+  [:id, :title].each do |lookup|
+    [nil, :historical].each do |edition|
+      it "rejects legacy #{ lookup } #{ edition || 'current' } without legacy SELECTs" do
+        path = lookup == :id ? "/wiki/#{ page.id }" : "/wiki/title/#{ tag_name.name }"
+        params = edition ? { version: first_revision.id } : { }
+        without_group_legacy_reads { get path, params: }
+        expect(response).to have_http_status(:not_found)
+      end
+    end
+
+    it "does not recognise legacy #{ lookup } existence" do
+      path = lookup == :id ? "/wiki/#{ page.id }" : "/wiki/title/#{ tag_name.name }"
+      without_group_legacy_reads { get "#{ path }/exists" }
+      expect(response).to have_http_status(:not_found)
+    end
   end
 
-  it 'shows legacy current and historical content by title' do
-    get "/wiki/title/#{ tag_name.name }"
-    expect(response).to have_http_status(:ok)
-    expect(json).to include('body' => 'after', 'revision_id' => last_revision.id)
-    get "/wiki/title/#{ tag_name.name }", params: { version: first_revision.id }
-    expect(response).to have_http_status(:ok)
-    expect(json).to include('body' => 'before', 'revision_id' => first_revision.id)
-  end
-
-  it 'recognises legacy IDs' do
-    get "/wiki/#{ page.id }/exists"
-    expect(response).to have_http_status(:no_content)
-  end
-
-  it 'recognises legacy titles' do
-    get "/wiki/title/#{ tag_name.name }/exists"
-    expect(response).to have_http_status(:no_content)
-  end
-
-  it 'diffs legacy revisions with explicit and current target' do
-    [last_revision.id, nil].each do |to|
-      get "/wiki/#{ page.id }/diff", params: { from: first_revision.id, to: }
+  ['/wiki', '/wiki/search', '/wiki/changes'].each do |path|
+    it "excludes unmigrated content from #{ path } without legacy SELECTs" do
+      without_group_legacy_reads { get path }
       expect(response).to have_http_status(:ok)
-      expect(json).to include(
-          'wiki_page_id' => page.id, 'title' => tag_name.name,
-          'older_revision_id' => first_revision.id, 'newer_revision_id' => last_revision.id,
-          'diff' => [{ 'type' => 'removed', 'content' => 'before' },
-                     { 'type' => 'added', 'content' => 'after' }])
+      expect(json).to eq([])
     end
   end
 
-  describe 'revision resource scope' do
-    let!(:other_page) do
-      Wiki::Commit.create_content!(
-          tag_name: create(:tag_name, name: 'Help_other_contract'),
-          body: 'other page history', created_by_user: user)
-    end
-    let(:other_revision) { other_page.current_revision }
-
-    it 'returns 404 when show specifies another page revision' do
-      get "/wiki/#{ page.id }", params: { version: other_revision.id }
-      expect(response).to have_http_status(:not_found)
-    end
-
-    it 'returns 404 when diff from belongs to another page' do
-      get "/wiki/#{ page.id }/diff",
-          params: { from: other_revision.id, to: last_revision.id }
-      expect(response).to have_http_status(:not_found)
-    end
-
-    it 'returns 404 when diff to belongs to another page' do
-      get "/wiki/#{ page.id }/diff",
-          params: { from: first_revision.id, to: other_revision.id }
-      expect(response).to have_http_status(:not_found)
-    end
-  end
-
-  it 'retains legacy history metadata and ordering' do
-    get '/wiki/changes', params: { id: page.id }
+  it 'returns empty scoped history without legacy SELECTs' do
+    without_group_legacy_reads { get '/wiki/changes', params: { id: page.id } }
     expect(response).to have_http_status(:ok)
-    expect(json.map { |row| row.fetch('revision_id') }).to eq(
-        [last_revision.id, first_revision.id])
-    expect(json.first).to include(
-        'pred' => first_revision.id, 'succ' => nil, 'kind' => 'content',
-        'message' => 'legacy edit', 'timestamp' => last_revision.created_at.iso8601(3),
-        'wiki_page' => { 'id' => page.id, 'title' => tag_name.name, 'deprecated_at' => nil },
-        'user' => { 'id' => user.id, 'name' => user.name })
+    expect(json).to eq([])
+  end
+
+  [false, true].each do |explicit|
+    it "rejects legacy diff with #{ explicit ? 'explicit' : 'current' } target" do
+      params = { from: first_revision.id }
+      params[:to] = last_revision.id if explicit
+      without_group_legacy_reads { get "/wiki/#{ page.id }/diff", params: }
+      expect(response).to have_http_status(:not_found)
+    end
   end
 end